US20110158645A1 - Plasmon-assisted wavelength-selective switch - Google Patents
Plasmon-assisted wavelength-selective switch Download PDFInfo
- Publication number
- US20110158645A1 US20110158645A1 US12/648,025 US64802509A US2011158645A1 US 20110158645 A1 US20110158645 A1 US 20110158645A1 US 64802509 A US64802509 A US 64802509A US 2011158645 A1 US2011158645 A1 US 2011158645A1
- Authority
- US
- United States
- Prior art keywords
- optical signals
- optical
- switch element
- optical signal
- plasmons
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000003287 optical effect Effects 0.000 claims abstract description 110
- 238000000034 method Methods 0.000 claims description 18
- 230000008878 coupling Effects 0.000 claims description 7
- 238000010168 coupling process Methods 0.000 claims description 7
- 238000005859 coupling reaction Methods 0.000 claims description 7
- WPYVAWXEWQSOGY-UHFFFAOYSA-N indium antimonide Chemical compound [Sb]#[In] WPYVAWXEWQSOGY-UHFFFAOYSA-N 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- 230000001427 coherent effect Effects 0.000 description 6
- 239000004973 liquid crystal related substance Substances 0.000 description 5
- 239000013307 optical fiber Substances 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 238000003780 insertion Methods 0.000 description 4
- 230000037431 insertion Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 210000002858 crystal cell Anatomy 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 241001507928 Aria Species 0.000 description 1
- 235000004494 Sorbus aria Nutrition 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000005314 correlation function Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000008672 reprogramming Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/29—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the position or the direction of light beams, i.e. deflection
- G02F1/295—Analog deflection from or in an optical waveguide structure]
- G02F1/2955—Analog deflection from or in an optical waveguide structure] by controlled diffraction or phased-array beam steering
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/008—Surface plasmon devices
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
- G02F2201/30—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00 grating
- G02F2201/305—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00 grating diffraction grating
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2203/00—Function characteristic
- G02F2203/10—Function characteristic plasmon
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0201—Add-and-drop multiplexing
- H04J14/0202—Arrangements therefor
- H04J14/021—Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM]
- H04J14/0212—Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM] using optical switches or wavelength selective switches [WSS]
Definitions
- a single optical fiber may convey signals at different wavelengths. Furthermore, via a wavelength-selective switch, it is possible to add or remove one or more carriers onto or from the optical fiber.
- WSS wavelength selective switch
- MEMS micro-electromechanical system
- LCOS Liquid-Crystal-on-Silicon
- LC Liquid Crystal
- each of pixels e.g., liquid crystal cells on a flat surface
- each antenna element contributes a coherent component of far-field signal in a particular direction.
- a LCOS device can steer beams in optical frequencies.
- FIG. 1 illustrates an exemplary optical network in which concepts described herein may be implemented
- FIGS. 2A and 2B are diagrams of exemplary components of a reconfigurable optical add-drop multiplexer of FIG. 1 ;
- FIG. 3 is a diagram of an exemplary plasmon-assisted wavelength-selective switch of FIG. 2A ;
- FIG. 4 is a diagram of an exemplary switch element of FIG. 3 in one configuration
- FIG. 5 illustrates the switching element of FIG. 3 in another configuration
- FIG. 6 is a flow diagram of an exemplary process for operating the plasmon-assisted wavelength-selective switch of FIG. 2A .
- a wavelength-selective switch may include gratings and surface plasmons. Upon receiving an input signal, the wavelength-selective switch may demultiplex the signal into coherent beams of different wavelengths. Furthermore, the gratings may steer the coherent beams in selected combinations to output ports. Because the energy of the plasmons may be coupled to that of the beams, the wavelength-selective switch may reduce or minimize any insertion loss in processing the input signal.
- FIG. 1 shows an exemplary optical network 100 in which the concepts described herein may be implemented.
- optical network 100 may include metro/regional networks 102 - 1 and 102 - 2 , long haul or ultra-long haul optical lines 104 , and edge network 106 .
- optical network 100 may include may include additional, fewer, or a different configuration of optical networks and optical lines than those illustrated in FIG. 1 .
- optical network 100 may include additional edge networks and/or metro/regional networks that are interconnected by Synchronous Optical Network (SONET) rings.
- SONET Synchronous Optical Network
- Metro/regional network 102 - 1 may include optical fibers and central office hubs that are interconnected by the optical fibers.
- the central office hubs one of which is illustrated as central office hub 108 - 1 , may include sites that house telecommunication equipment, including switches, optical line terminals, etc.
- central office hub 108 - 1 may provide telecommunication services to subscribers, such as telephone service, access to the Internet, cable television programs, etc., via optical line terminals.
- Metro/regional network 102 - 2 may include similar components as metro/regional network 102 - 1 and may operate similarly. In FIG.
- metro/regional network 102 - 2 is illustrated as including central office hub 108 - 2 , which may include similar components as central office hub 108 - 1 and may operate similarly.
- Long haul optical lines 104 may include optical fibers that extend from metro/regional optical network 102 - 1 to metro/regional optical network 102 - 2 .
- Edge network 106 may include optical networks that provide user access to metro/regional optical network 102 - 2 . As shown in FIG. 1 , edge network 106 may include access points 110 - 1 and 110 - 2 (e.g., office buildings, residential area, etc.) via which end customers may obtain communication services from central office hub 108 - 2 .
- access points 110 - 1 and 110 - 2 e.g., office buildings, residential area, etc.
- networks 102 - 1 , 102 - 2 , 104 , and 106 may include reconfigurable optical add-drop multiplexers (ROADMs) 112 - 1 through 112 - 5 (collectively “ROADMs 112 ” and individually “ROADM 112 - x ”).
- ROADMs 112 - x may add or drop optical signals of particular wavelengths to/from the network and provide for part of wavelength division multiplexing (WDM) in network 100 .
- WDM wavelength division multiplexing
- the configuration of ROADMs 112 may be controlled remotely (e.g., from central office hub 112 - 1 ).
- ROADM 112 - x may include plasmon-assisted (PA) wavelength-selective switches.
- PA plasmon-assisted
- the term “plasmon-assisted (PA) wavelength selective switch” may refer to a wavelength selective switch in which the power of generated plasmon is coupled back to an output optical wave, potentially significantly decreasing insertion loss of the wavelength selective switch.
- the grating structure in a switch element through which the plasmons propagate can be programmed or reprogrammed to direct the output beam to a particular output port.
- FIGS. 2A and 2B are diagrams of exemplary components of PA wavelength-selective switches of ROADM 112 - x .
- FIG. 2A illustrates PA wavelength-selective switch 202 .
- PA wavelength-selective switch 202 may include a demultiplexer 206 , lens 208 , switch array 210 , lens 212 , output ports 214 - 1 through 214 -M (collectively “output ports 214 ” and individually “output port 214 - x ”), and controller 216 .
- PA wavelength-selective switch 202 may include additional, fewer, or different arrangement of components than those illustrated in FIG. 2A .
- PA wavelength-selective switch 202 may include collimators between demultiplexer 206 and lens 208 , or collimators between lens 212 and output ports 214 .
- PA wavelength-selective switch 202 may provide different internal geometry to employ a single lens in place of lenses 208 and 210 .
- Demultiplexer 206 may receive an input beam and spatially separate the input beam into beams of different wavelengths. For example, demultiplexer 206 may separate a white beam into red, green, and blue beams. Lens 208 may focus each of the beams of different wavelengths from demultiplexer 206 onto switch array 210 .
- Switch array 210 may include switch elements 210 - 1 through 210 -N (collectively “switch elements 210 ” and individually “switch element 210 - x ”). Each switch element 210 - x may receive an input beam of a particular wavelength and direct the beam to one of output ports 214 - 1 through 214 -M. By controlling switch elements 210 , PA wavelength-selective switch 202 may select output beams of particular wavelengths and direct the beams to specific output ports 214 .
- Lens 212 may focus each of the beams from switch array 210 into output ports 214 .
- Output port 214 - x may receive a combination of selected beams of particular wavelengths from switch elements 210 and output the combination of beams.
- Controller 216 may configure switch elements 210 (e.g., configure switch element 210 - x to direct a beam to a particular output port 214 - x ).
- controller 216 may communicate with an external device in configuring PA wavelength-selective switch 202 .
- FIG. 2B illustrates PA wavelength-selective switch 204 .
- PA wavelength-selective switch 204 may include components that correspond to the components of PA wavelength-selective switch 202 . However, in PA wavelength-selective switch 204 , optical signals flow in the reverse direction of the optical signals in PA wavelength-selective switch 202 illustrated in FIG. 2A .
- PA wavelength-selective switch 204 may include input ports 220 , lens 222 , switch array 224 , lens 226 , multiplexer 228 , and controller 230 . As in the case of PA wavelength-selective switch 202 , PA wavelength-selective switch 204 may include additional, fewer, or different components than those illustrated in FIG. 2B .
- Input ports 220 may receive optical beams/signals and direct them to switch elements 224 in switch array 224 .
- Lens 222 may focus each of the beams from input ports 220 onto switch array 224 .
- Each switch element 224 - x may receive an input beam from input ports 220 and direct the beam to multiplexer 228 .
- Lens 226 may focus the beams from switch array 224 onto multiplexer 228 .
- Multiplexer 228 may combine the beams of different wavelengths from switch array 224 and output them as an optical beam from PA wavelength-selective switch 204 .
- Controller 230 may control/configure switch elements 224 . Furthermore, controllers 230 may communicate with an external device in configuring PA wavelength-selective switch 204 .
- PA wavelength-selective switch 202 may operate in conjunction with PA wavelength-selective switch 204 .
- each of output ports 214 may be connected to each of input ports 220 , except for a number of output ports (e.g., output ports 214 -(M- 1 ) and 214 -M) and input ports (e.g., input ports 220 -(M- 1 ) and 220 -M) via which beams of specific wavelengths may be added and/or dropped from the beam that travels from the input of demultiplexer 206 to the output of multiplexer 228 . That is, as optical signals at different wavelengths propagate through ROADM 112 - x , selected optical signals at particular wavelengths may be added or dropped via a number of input ports 220 and output ports 214 .
- FIG. 3 is a diagram of an exemplary PA wavelength-selective switch 202 .
- multiplexer 206 of PA wavelength-selective switch 202 may include a diffraction grating 302 .
- Diffraction grating 302 may scatter an input optical beam into beams of different wavelengths ⁇ 1 , ⁇ 2 . . . , and ⁇ N .
- Each of the diffracted beams may be directed to a corresponding switch element 210 - x.
- each switch element 210 - x may diffract a beam of light around particular wavelength ⁇ x to output port 214 - y . Accordingly, each output port 214 - x may carry a signal that is a combination of beams from different switch elements 210 .
- FIG. 4 is a diagram of switch element 210 - x in one configuration.
- switch element 210 - x may include a body 402 , with an aperture 404 and a grating structure 406 on a surface facing away from incident beam 410 .
- switch element 210 - x may include additional or different components (e.g., electrical contacts, mechanical structures, etc.).
- Body 402 may be made of metal or semiconductor (e.g., indium antimonide (InSb)). In some implementations, body 402 may transmit some of incident beam 410 and allow the transmitting beam to interact with grating structure 406 . Aperture 404 may include space via which a portion of beam 410 may be sent through body 402 .
- InSb indium antimonide
- Grating structure 406 may include grooves, micro-electro-mechanical systems (MEMS) structures, and/or other types of grating elements (e.g., grating elements 406 - 1 and 406 - 2 ) that guide incident beam 410 into diffracted beam 412 in accordance with signals/instructions from controller 216 .
- MEMS micro-electro-mechanical systems
- grating elements 406 - 1 and 406 - 2 grating elements that guide incident beam 410 into diffracted beam 412 in accordance with signals/instructions from controller 216 .
- incident beam 410 may hit grating structure 406 from the front, rather than from the back ( FIG. 5 ).
- Grating elements 406 - 1 and 406 - 2 (or other grating elements not labeled in FIG. 4 ) in grating structure 406 may be sufficiently spaced apart (e.g., distance d) to allow plasmons 408 to exist there between.
- plasmons 408 may be localized or confined at or near the surface of body 402 (e.g., surface plasmons).
- plasmons 408 may be created by the interaction between electromagnetic field/electrons and metal surface (e.g., a surface on body 402 ). That is, plasmons 408 may be generated or induced via electron injection or incident light from another component (not shown) to body 402 .
- PA wavelength-selective switch 202 may incur small or no insertion loss.
- FIG. 5 illustrates switching element 210 - x in another configuration. Due to the different arrangement (not shown) of components in PA wavelength selective switch 202 (e.g., lens, mirrors, etc.), beam 410 in FIG. 5 is incident on body 402 from the front, rather than from the back as illustrated in FIG. 4 .
- PA wavelength selective switch 202 e.g., lens, mirrors, etc.
- FIG. 5 illustrates coupling between beams and plasmons 408 via grating structure 406 .
- the coupling relationship between plasmons 408 and beam 412 illustrates effects of modifying the periodicity of grating structure 406 and angle of incidence ⁇ i for steering diffracted beam 412 .
- E C E 0 exp(i (k x x+k z z ⁇ t)), where E 0 is the magnitude of the wave, k x is the wave number in x-axis, k z is the wave number in the z-axis, and ⁇ is the frequency.
- k x is the wave number of beams in region z p
- ⁇ i is the angle of incidence
- m is an integer
- d j is the period of j th Fourier component of groove structure 406 .
- the overall effect of groove structure 406 can be obtained by summing up expression (2) over different Fourier components of groove structure 406 :
- T is a transmission function
- ⁇ is a solid angle over which intensity of diffracted is to be determined
- I is the intensity of diffracted beam 412
- I 0 is the intensity of incident beam 410
- S is a Fourier transform of a Gaussian correlation function
- W 2 is a radiation pattern from a single dipole at body 402 /dielectric (e.g., air) interface.
- T, S, and W may depend on angle ⁇ i , k s , dielectric functions/constants in body 402 and in z p .
- Expression (4) illustrates the coupling relationship between each of plasmons 408 and beams 412 and how modifying the width d between grooves in grating structure 406 (e.g., the period of grating structure 406 ) and/or other device parameters may steer diffracted beam 412 in a particular direction.
- additional refinements may be made to expression (4), they are not described here for the purpose of simplicity and ease of understanding.
- FIG. 6 is a flow diagram of an exemplary process 600 that is associated with operation of PA wavelength-selective switch 202 .
- Processing 600 may include receiving an optical signal at an input port of demultiplexer 208 (block 602 ).
- PA wavelength-selective switch 202 may process the signal (e.g., focus the signal via lens 208 , collimate the signal, etc.) (block 604 ).
- PA wavelength-selective switch 202 may demultiplex the optical signal into multiple signals (block 606 ).
- demultiplexer 208 may include diffraction grating (e.g., diffraction grating 302 ) that separates the optical signal into multiple optical signals at different wavelengths.
- Each of the multiple signals may be guided to switch element 210 - x (block 608 ).
- directing the multiple signals may require additional processing (e.g., via lens, mirror, etc.).
- Switch element 210 - x may direct a received optical beam from demultiplexer 206 to a particular output port 214 - x (block 610 ). Directing the received optical beam may include changing the period of grating structure 406 (e.g., reprogramming) or reconfiguring MEMS structures in switch element 210 - x via controller 216 . This may modify both the direction of the beam as well as the degree to which plasmons 408 are coupled to beams 412 . As the consequence of switch elements 210 directing the multiple optical signals, each output port 214 - x may receive a combination of the optical signals at different carrier wavelengths from one or more switch elements 214 .
- grating structure 406 e.g., reprogramming
- MEMS structures in switch element 210 - x via controller 216 . This may modify both the direction of the beam as well as the degree to which plasmons 408 are coupled to beams 412 .
- each output port 214 - x may receive a combination
- PA wavelength-selective switch 202 may process the optical signals from switch elements 210 (block 612 ). As described, above, processing the optical signals may include further focusing/defocusing, collimating, etc. PA wavelength-selective switch 202 may output the processed optical signals from output ports 214 (block 614 ). One or more of optical signals that are received at one of output ports 214 may be dropped by PA wavelength-selective switch 202 .
- PA wavelength-selective switch 202 may demultiplex an optical signal into multiple optical signals, drop one or more of the multiple signals at specific wavelengths, and output the remaining multiple optical signals.
- PA wavelength-selective switch 204 may perform a process that is the reverse of process 600 (e.g., receive multiple optical signals), add one or more signals at specific wavelengths, and multiplex the multiple signals and the added signals into one optical signal.
- PA wavelength-selective switches 202 and 204 may steer coherent beams via grating structure 406 in switch elements 214 / 224 .
- grating structure 406 in switch element 210 - x may steer coherent beams to output ports 214 .
- grating structure 206 may receive coherent beams from input ports 220 .
- using PA wavelength-selective switch 202 / 204 may reduce or minimize an insertion loss in processing the input signal.
- non-dependent blocks may represent blocks that can be performed in parallel.
Landscapes
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
Abstract
Description
- In optical communications, a single optical fiber may convey signals at different wavelengths. Furthermore, via a wavelength-selective switch, it is possible to add or remove one or more carriers onto or from the optical fiber.
- Today, there are three predominant technologies for switching beams of light within a wavelength selective switch (WSS). These technologies are based on using a micro-electromechanical system (MEMS) array, Liquid-Crystal-on-Silicon (LCOS) array, and Liquid Crystal (LC) elements array. Independently of the switching technology used within a WSS, the optical path of the beam of light in the WSS passes through a diffractive structure that implements channel demultuplexing before a switching function. A switching element (MEMS, LCOS, or LC) that implements the switching function directs each channel to a designated output port.
- In a WSS that uses the LCOS, each of pixels (e.g., liquid crystal cells on a flat surface) in an array is electronically and individually controlled, in a manner analogous to that in which an individual element in a phased array antenna is controlled to change the phase of the signal reflected from an antenna element. Each antenna element contributes a coherent component of far-field signal in a particular direction. With each liquid crystal cell acting analogous to a phase-changing antenna element, a LCOS device can steer beams in optical frequencies.
-
FIG. 1 illustrates an exemplary optical network in which concepts described herein may be implemented; -
FIGS. 2A and 2B are diagrams of exemplary components of a reconfigurable optical add-drop multiplexer ofFIG. 1 ; -
FIG. 3 is a diagram of an exemplary plasmon-assisted wavelength-selective switch ofFIG. 2A ; -
FIG. 4 is a diagram of an exemplary switch element ofFIG. 3 in one configuration; -
FIG. 5 illustrates the switching element ofFIG. 3 in another configuration; and -
FIG. 6 is a flow diagram of an exemplary process for operating the plasmon-assisted wavelength-selective switch ofFIG. 2A . - The following detailed description refers to the accompanying drawings. The same reference numbers in different drawings may identify the same or similar elements.
- As described below, a wavelength-selective switch may include gratings and surface plasmons. Upon receiving an input signal, the wavelength-selective switch may demultiplex the signal into coherent beams of different wavelengths. Furthermore, the gratings may steer the coherent beams in selected combinations to output ports. Because the energy of the plasmons may be coupled to that of the beams, the wavelength-selective switch may reduce or minimize any insertion loss in processing the input signal.
-
FIG. 1 shows an exemplaryoptical network 100 in which the concepts described herein may be implemented. As shown,optical network 100 may include metro/regional networks 102-1 and 102-2, long haul or ultra-long hauloptical lines 104, andedge network 106. Depending on the implementation,optical network 100 may include may include additional, fewer, or a different configuration of optical networks and optical lines than those illustrated inFIG. 1 . For example, in one implementation,optical network 100 may include additional edge networks and/or metro/regional networks that are interconnected by Synchronous Optical Network (SONET) rings. - Metro/regional network 102-1 may include optical fibers and central office hubs that are interconnected by the optical fibers. The central office hubs, one of which is illustrated as central office hub 108-1, may include sites that house telecommunication equipment, including switches, optical line terminals, etc. In addition to being connected to other central offices, central office hub 108-1 may provide telecommunication services to subscribers, such as telephone service, access to the Internet, cable television programs, etc., via optical line terminals. Metro/regional network 102-2 may include similar components as metro/regional network 102-1 and may operate similarly. In
FIG. 1 , metro/regional network 102-2 is illustrated as including central office hub 108-2, which may include similar components as central office hub 108-1 and may operate similarly. Long hauloptical lines 104 may include optical fibers that extend from metro/regional optical network 102-1 to metro/regional optical network 102-2. - Edge
network 106 may include optical networks that provide user access to metro/regional optical network 102-2. As shown inFIG. 1 ,edge network 106 may include access points 110-1 and 110-2 (e.g., office buildings, residential area, etc.) via which end customers may obtain communication services from central office hub 108-2. - In
FIG. 1 , networks 102-1, 102-2, 104, and 106 may include reconfigurable optical add-drop multiplexers (ROADMs) 112-1 through 112-5 (collectively “ROADMs 112” and individually “ROADM 112-x”). Each ROADM 112-x may add or drop optical signals of particular wavelengths to/from the network and provide for part of wavelength division multiplexing (WDM) innetwork 100. The configuration of ROADMs 112 may be controlled remotely (e.g., from central office hub 112-1). In some implementations, ROADM 112-x may include plasmon-assisted (PA) wavelength-selective switches. As used herein, the term “plasmon-assisted (PA) wavelength selective switch” may refer to a wavelength selective switch in which the power of generated plasmon is coupled back to an output optical wave, potentially significantly decreasing insertion loss of the wavelength selective switch. The grating structure in a switch element through which the plasmons propagate can be programmed or reprogrammed to direct the output beam to a particular output port. -
FIGS. 2A and 2B are diagrams of exemplary components of PA wavelength-selective switches of ROADM 112-x.FIG. 2A illustrates PA wavelength-selective switch 202. As shown inFIG. 2A , PA wavelength-selective switch 202 may include ademultiplexer 206,lens 208,switch array 210,lens 212, output ports 214-1 through 214-M (collectively “output ports 214” and individually “output port 214-x”), andcontroller 216. - Depending on the implementation, PA wavelength-
selective switch 202 may include additional, fewer, or different arrangement of components than those illustrated inFIG. 2A . For example, in one implementation, PA wavelength-selective switch 202 may include collimators betweendemultiplexer 206 andlens 208, or collimators betweenlens 212 andoutput ports 214. In another example, in a different implementation, PA wavelength-selective switch 202 may provide different internal geometry to employ a single lens in place oflenses - Demultiplexer 206 may receive an input beam and spatially separate the input beam into beams of different wavelengths. For example,
demultiplexer 206 may separate a white beam into red, green, and blue beams.Lens 208 may focus each of the beams of different wavelengths fromdemultiplexer 206 ontoswitch array 210. -
Switch array 210 may include switch elements 210-1 through 210-N (collectively “switch elements 210” and individually “switch element 210-x”). Each switch element 210-x may receive an input beam of a particular wavelength and direct the beam to one of output ports 214-1 through 214-M. By controllingswitch elements 210, PA wavelength-selective switch 202 may select output beams of particular wavelengths and direct the beams tospecific output ports 214. -
Lens 212 may focus each of the beams fromswitch array 210 intooutput ports 214. Output port 214-x may receive a combination of selected beams of particular wavelengths fromswitch elements 210 and output the combination of beams.Controller 216 may configure switch elements 210 (e.g., configure switch element 210-x to direct a beam to a particular output port 214-x). Furthermore,controller 216 may communicate with an external device in configuring PA wavelength-selective switch 202. -
FIG. 2B illustrates PA wavelength-selective switch 204. PA wavelength-selective switch 204 may include components that correspond to the components of PA wavelength-selective switch 202. However, in PA wavelength-selective switch 204, optical signals flow in the reverse direction of the optical signals in PA wavelength-selective switch 202 illustrated inFIG. 2A . - As shown, PA wavelength-
selective switch 204 may includeinput ports 220,lens 222,switch array 224,lens 226,multiplexer 228, andcontroller 230. As in the case of PA wavelength-selective switch 202, PA wavelength-selective switch 204 may include additional, fewer, or different components than those illustrated inFIG. 2B . -
Input ports 220 may receive optical beams/signals and direct them to switchelements 224 inswitch array 224.Lens 222 may focus each of the beams frominput ports 220 ontoswitch array 224. Each switch element 224-x may receive an input beam frominput ports 220 and direct the beam tomultiplexer 228.Lens 226 may focus the beams fromswitch array 224 ontomultiplexer 228.Multiplexer 228 may combine the beams of different wavelengths fromswitch array 224 and output them as an optical beam from PA wavelength-selective switch 204.Controller 230 may control/configureswitch elements 224. Furthermore,controllers 230 may communicate with an external device in configuring PA wavelength-selective switch 204. - In ROADM 112-x, PA wavelength-
selective switch 202 may operate in conjunction with PA wavelength-selective switch 204. In such an implementation, each ofoutput ports 214 may be connected to each ofinput ports 220, except for a number of output ports (e.g., output ports 214-(M-1) and 214-M) and input ports (e.g., input ports 220-(M-1) and 220-M) via which beams of specific wavelengths may be added and/or dropped from the beam that travels from the input ofdemultiplexer 206 to the output ofmultiplexer 228. That is, as optical signals at different wavelengths propagate through ROADM 112-x, selected optical signals at particular wavelengths may be added or dropped via a number ofinput ports 220 andoutput ports 214. -
FIG. 3 is a diagram of an exemplary PA wavelength-selective switch 202. For the purpose of simplicity and ease of understanding,FIG. 3 does not show some of the components ofFIG. 2A . As shown inFIG. 3 ,multiplexer 206 of PA wavelength-selective switch 202 may include adiffraction grating 302.Diffraction grating 302 may scatter an input optical beam into beams of different wavelengths λ1, λ2 . . . , and λN. Each of the diffracted beams may be directed to a corresponding switch element 210-x. - As further shown, each switch element 210-x may diffract a beam of light around particular wavelength λx to output port 214-y. Accordingly, each output port 214-x may carry a signal that is a combination of beams from
different switch elements 210. -
FIG. 4 is a diagram of switch element 210-x in one configuration. As shown, switch element 210-x may include abody 402, with anaperture 404 and agrating structure 406 on a surface facing away fromincident beam 410. Depending on the implementation, switch element 210-x may include additional or different components (e.g., electrical contacts, mechanical structures, etc.). -
Body 402 may be made of metal or semiconductor (e.g., indium antimonide (InSb)). In some implementations,body 402 may transmit some ofincident beam 410 and allow the transmitting beam to interact withgrating structure 406.Aperture 404 may include space via which a portion ofbeam 410 may be sent throughbody 402. -
Grating structure 406 may include grooves, micro-electro-mechanical systems (MEMS) structures, and/or other types of grating elements (e.g., grating elements 406-1 and 406-2) that guideincident beam 410 into diffractedbeam 412 in accordance with signals/instructions fromcontroller 216. In an implementation where the spatial geometry of the components in wavelength-selective switch 202 is different than that illustrated inFIG. 4 ,incident beam 410 may hitgrating structure 406 from the front, rather than from the back (FIG. 5 ). - Grating elements 406-1 and 406-2 (or other grating elements not labeled in
FIG. 4 ) in gratingstructure 406 may be sufficiently spaced apart (e.g., distance d) to allowplasmons 408 to exist there between. The term “plasmon,” as used herein, includes a unit or quantum of resonant oscillation in electron density inbody 402. As shown inFIG. 4 ,plasmons 408 may be localized or confined at or near the surface of body 402 (e.g., surface plasmons). Typically,plasmons 408 may be created by the interaction between electromagnetic field/electrons and metal surface (e.g., a surface on body 402). That is,plasmons 408 may be generated or induced via electron injection or incident light from another component (not shown) tobody 402. - In the configuration illustrated in
FIG. 4 , because the energy ofplasmons 408 may couple with the energy of diffractedbeam 412, PA wavelength-selective switch 202 may incur small or no insertion loss. -
FIG. 5 illustrates switching element 210-x in another configuration. Due to the different arrangement (not shown) of components in PA wavelength selective switch 202 (e.g., lens, mirrors, etc.),beam 410 inFIG. 5 is incident onbody 402 from the front, rather than from the back as illustrated inFIG. 4 . - In addition,
FIG. 5 illustrates coupling between beams andplasmons 408 via gratingstructure 406. The coupling relationship betweenplasmons 408 andbeam 412 illustrates effects of modifying the periodicity ofgrating structure 406 and angle of incidence θi for steering diffractedbeam 412. - To obtain an expression approximating the coupling, it may be useful to obtain an expression for the wave number ks for
plasmons 408. Assume thatbody 402 is oriented in accordance with coordinateaxis 502, and that far-field beams in an area facing the front surface ofbody 402 include diffractedbeam 412. Assuming that the far-field beams are described by the real part of complex electromagnetic wave EC, it is possible to write, EC=E0 exp(i (kxx+kzz−ωt)), where E0 is the magnitude of the wave, kx is the wave number in x-axis, kz is the wave number in the z-axis, and ω is the frequency. In addition, assume thatgrating structure 406 on the surface ofbody 402 is a sinusoid of a single period. Matching boundary conditions at areas zp and zM, the dispersion relation for ks on the surface ofbody 402 becomes: -
k s =k x sin θi±2πm/d=(ω/c)sin θi±2πm/d j (2) - In expression (2), kx is the wave number of beams in region zp, θi is the angle of incidence, m is an integer, and dj is the period of jth Fourier component of
groove structure 406. The overall effect ofgroove structure 406 can be obtained by summing up expression (2) over different Fourier components of groove structure 406: -
- Given expression (3), it is possible to determine a coupling between
plasmons 410 and diffractedbeam 412. Assume that T is a transmission function, Ω is a solid angle over which intensity of diffracted is to be determined, I is the intensity of diffractedbeam 412, I0 is the intensity ofincident beam 410, S is a Fourier transform of a Gaussian correlation function, and W2 is a radiation pattern from a single dipole atbody 402/dielectric (e.g., air) interface. Each of T, S, and W may depend on angle θi, ks, dielectric functions/constants inbody 402 and in zp. Then, it is possible to write: -
(1/I 0)dI/dΩ=(1/4)(ω/c)4 |S| 2 |T| 2 |W(θi)|2 (4). - Expression (4) illustrates the coupling relationship between each of
plasmons 408 andbeams 412 and how modifying the width d between grooves in grating structure 406 (e.g., the period of grating structure 406) and/or other device parameters may steer diffractedbeam 412 in a particular direction. Although additional refinements may be made to expression (4), they are not described here for the purpose of simplicity and ease of understanding. -
FIG. 6 is a flow diagram of anexemplary process 600 that is associated with operation of PA wavelength-selective switch 202. Processing 600 may include receiving an optical signal at an input port of demultiplexer 208 (block 602). In some implementations, PA wavelength-selective switch 202 may process the signal (e.g., focus the signal vialens 208, collimate the signal, etc.) (block 604). - PA wavelength-
selective switch 202 may demultiplex the optical signal into multiple signals (block 606). In one implementation,demultiplexer 208 may include diffraction grating (e.g., diffraction grating 302) that separates the optical signal into multiple optical signals at different wavelengths. - Each of the multiple signals may be guided to switch element 210-x (block 608). In some implementations, directing the multiple signals may require additional processing (e.g., via lens, mirror, etc.).
- Switch element 210-x may direct a received optical beam from
demultiplexer 206 to a particular output port 214-x (block 610). Directing the received optical beam may include changing the period of grating structure 406 (e.g., reprogramming) or reconfiguring MEMS structures in switch element 210-x viacontroller 216. This may modify both the direction of the beam as well as the degree to whichplasmons 408 are coupled to beams 412. As the consequence ofswitch elements 210 directing the multiple optical signals, each output port 214-x may receive a combination of the optical signals at different carrier wavelengths from one ormore switch elements 214. - PA wavelength-
selective switch 202 may process the optical signals from switch elements 210 (block 612). As described, above, processing the optical signals may include further focusing/defocusing, collimating, etc. PA wavelength-selective switch 202 may output the processed optical signals from output ports 214 (block 614). One or more of optical signals that are received at one ofoutput ports 214 may be dropped by PA wavelength-selective switch 202. - In
process 600, PA wavelength-selective switch 202 may demultiplex an optical signal into multiple optical signals, drop one or more of the multiple signals at specific wavelengths, and output the remaining multiple optical signals. In contrast, PA wavelength-selective switch 204 may perform a process that is the reverse of process 600 (e.g., receive multiple optical signals), add one or more signals at specific wavelengths, and multiplex the multiple signals and the added signals into one optical signal. - In manipulating the beams within, PA wavelength-
selective switches structure 406 inswitch elements 214/224. In PA wavelength-selective switch 202,grating structure 406 in switch element 210-x may steer coherent beams tooutput ports 214. In PA wavelength-selective switch 204,grating structure 206 may receive coherent beams frominput ports 220. In PA wavelength-selective switches plasmon 408 is coupled to the beams, using PA wavelength-selective switch 202/204 may reduce or minimize an insertion loss in processing the input signal. - In this specification, various preferred embodiments have been described with reference to the accompanying drawings. It will, however, be evident that various modifications and changes may be made thereto, and additional embodiments may be implemented, without departing from the broader scope of the invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative rather than restrictive sense.
- Furthermore, while a series of blocks have been described with regard to the process illustrated in
FIG. 6 , the order of the blocks may be modified in other implementations. In addition, non-dependent blocks may represent blocks that can be performed in parallel. - It will be apparent that aspects described herein may be implemented in many different forms of software, firmware, and hardware in the implementations illustrated in the figures. The actual software code or specialized control hardware used to implement aspects does not limit the invention. Thus, the operation and behavior of the aspects were described without reference to the specific software code—it being understood that software and control hardware can be designed to implement the aspects based on the description herein.
- No element, block, or instruction used in the present application should be construed as critical or essential to the implementations described herein unless explicitly described as such. Also, as used herein, the article “a” is intended to include one or more items. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.
Claims (20)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/648,025 US8295699B2 (en) | 2009-12-28 | 2009-12-28 | Plasmon-assisted wavelength-selective switch |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/648,025 US8295699B2 (en) | 2009-12-28 | 2009-12-28 | Plasmon-assisted wavelength-selective switch |
Publications (2)
Publication Number | Publication Date |
---|---|
US20110158645A1 true US20110158645A1 (en) | 2011-06-30 |
US8295699B2 US8295699B2 (en) | 2012-10-23 |
Family
ID=44187727
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/648,025 Active 2031-04-27 US8295699B2 (en) | 2009-12-28 | 2009-12-28 | Plasmon-assisted wavelength-selective switch |
Country Status (1)
Country | Link |
---|---|
US (1) | US8295699B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20160036529A1 (en) * | 2013-03-15 | 2016-02-04 | Bae Systems Plc | Directional multiband antenna |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6282005B1 (en) * | 1998-05-19 | 2001-08-28 | Leo J. Thompson | Optical surface plasmon-wave communications systems |
US7010183B2 (en) * | 2002-03-20 | 2006-03-07 | The Regents Of The University Of Colorado | Surface plasmon devices |
US7039315B2 (en) * | 2003-01-24 | 2006-05-02 | Lucent Technologies Inc. | Optical routers based on surface plasmons |
US20080193133A1 (en) * | 2006-09-11 | 2008-08-14 | Krug William P | Scalable reconfigurable optical add-drop multiplexer |
US20080212975A1 (en) * | 2006-12-27 | 2008-09-04 | Alexander Burenkov | Interconnection network between semiconductor structures, integrated circuit and method for transmitting signals |
US20100129085A1 (en) * | 2006-03-23 | 2010-05-27 | Smolyaninov Igor I | Plasmonic systems and devices utilizing surface plasmon polariton |
US20110129183A1 (en) * | 2006-06-19 | 2011-06-02 | Searete Llc | Plasmon multiplexing |
US8086108B2 (en) * | 2007-07-25 | 2011-12-27 | Panasonic Corporation | Optical transmission/reception device and optical communication system using the same |
US8135277B2 (en) * | 2007-12-06 | 2012-03-13 | Inha-Industry Partnership Institute | Delayed optical router/switch |
-
2009
- 2009-12-28 US US12/648,025 patent/US8295699B2/en active Active
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6282005B1 (en) * | 1998-05-19 | 2001-08-28 | Leo J. Thompson | Optical surface plasmon-wave communications systems |
US7010183B2 (en) * | 2002-03-20 | 2006-03-07 | The Regents Of The University Of Colorado | Surface plasmon devices |
US7039315B2 (en) * | 2003-01-24 | 2006-05-02 | Lucent Technologies Inc. | Optical routers based on surface plasmons |
US20100129085A1 (en) * | 2006-03-23 | 2010-05-27 | Smolyaninov Igor I | Plasmonic systems and devices utilizing surface plasmon polariton |
US20110129183A1 (en) * | 2006-06-19 | 2011-06-02 | Searete Llc | Plasmon multiplexing |
US20080193133A1 (en) * | 2006-09-11 | 2008-08-14 | Krug William P | Scalable reconfigurable optical add-drop multiplexer |
US20080212975A1 (en) * | 2006-12-27 | 2008-09-04 | Alexander Burenkov | Interconnection network between semiconductor structures, integrated circuit and method for transmitting signals |
US8086108B2 (en) * | 2007-07-25 | 2011-12-27 | Panasonic Corporation | Optical transmission/reception device and optical communication system using the same |
US8135277B2 (en) * | 2007-12-06 | 2012-03-13 | Inha-Industry Partnership Institute | Delayed optical router/switch |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20160036529A1 (en) * | 2013-03-15 | 2016-02-04 | Bae Systems Plc | Directional multiband antenna |
US9692512B2 (en) * | 2013-03-15 | 2017-06-27 | Bae Systems Plc | Directional multiband antenna |
Also Published As
Publication number | Publication date |
---|---|
US8295699B2 (en) | 2012-10-23 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP6823668B2 (en) | Optical signal processor | |
US7376311B2 (en) | Method and apparatus for wavelength-selective switches and modulators | |
US7509048B2 (en) | Method and apparatus for optical signal processing using an optical tapped delay line | |
JP6609789B2 (en) | Wavelength selective switch array | |
US20130272650A1 (en) | Wavelength cross connect device | |
Suzuki et al. | Application of waveguide/free-space optics hybrid to ROADM device | |
EP1445631A1 (en) | Optical device with slab waveguide and channel waveguides on substrate | |
JP2006243571A (en) | Wavelength selective switch | |
US11728919B2 (en) | Optical communications apparatus and wavelength selection method | |
Frisken et al. | Wavelength-selective reconfiguration in transparent agile optical networks | |
JP2020535469A (en) | Wavelength selection switch, orientation direction acquisition method, liquid crystal on-silicon and its manufacturing method | |
EP3522408B1 (en) | Optical signal transmission method and device, and wavelength selective switch | |
KR100899808B1 (en) | Wavelength selective switch | |
CN110494781A (en) | Wavelength selecting method and wavelength-selective switches | |
EP2073046A1 (en) | Wavelength selective switch | |
CN103472538B (en) | Based on the wavelength-selective switches of micro deformable mirror | |
JP2004523162A (en) | WDM optical communication system | |
US8295699B2 (en) | Plasmon-assisted wavelength-selective switch | |
EP1299967A1 (en) | Bragg grating assisted mmimi-coupler for tunable add-drop multiplexing | |
Sorimoto et al. | MEMS mirror with slot structures suitable for flexible-grid WSS | |
KR100264950B1 (en) | Wavelength-variable light extraction / transmission filter for WDM communication without feedback noise | |
CN114063215B (en) | Wavelength selective switch, optical switching device and system | |
SE526498C2 (en) | Optical coupler used in fiber optic network, has deflectors to couple radiation propagating through waveguides with common radiation modes, defined by adjustable geometrical and material properties of coupler | |
JP6225075B2 (en) | Wavelength selective switch | |
Yu et al. | Volume phase grating based flat-top passband response dense wavelength division multiplexers |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: VERIZON PATENT AND LICENSING, INC., NEW JERSEY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:EGOROV, ROMAN;ELBY, STUART;REEL/FRAME:023709/0357 Effective date: 20091228 |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
AS | Assignment |
Owner name: CIENA CORPORATION, MARYLAND Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:VERIZON PATENT LICENSING, INC.;REEL/FRAME:040054/0950 Effective date: 20160909 |
|
FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
MAFP | Maintenance fee payment |
Free format text: PAYMENT OF MAINTENANCE FEE, 8TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1552); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY Year of fee payment: 8 |